foo.cc: In function 'void dfs(int, int)':
foo.cc:46:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   46 |     if(p!=i)
      |       ^
foo.cc:53:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   53 |     if(tmp+1>>1){g[q]=f[q]+tmp;}
      |        ~~~^~

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